Re: [TLS] Thoughts on Version Intolerance

Kyle Rose <> Wed, 20 July 2016 12:49 UTC

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From: Kyle Rose <>
Date: Wed, 20 Jul 2016 14:49:03 +0200
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To: Hubert Kario <>
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Subject: Re: [TLS] Thoughts on Version Intolerance
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> it's not IETF's fault that the implementers add unspecified by IETF
> restrictions and limitations to parsers of Client Hello messages or that
> they can't handle handshake messages split over multiple record layer
> messages, despite the standard being very explicit in that they MUST
> support this

When the failures are limited to obscure implementations, and/or popular
ones with a hope of being updated, I'm in the "fix your shit" camp.

When a substantial fraction of the internet breaks, this approach is less
clearly the right one because it can result in the never-ending downgrade
dance, or in limited deployment of new versions/ossification. I hope (with
no real evidence) that given the strong level of involvement of the major
browsers in 1.3 development that advantage goes to the client.